F = net force acting on the elevator in upward direction = 3000 N
m = mass of the elevator = 1200 kg
a = acceleration of the elevator = ?
Acceleration of the elevator is given as
a = F/m
a = 3000/1200
a = 2.5 m/s²
v₀ = initial velocity of the elevator = 0 m/s
Y = displacement of the elevator = 15 m
t = time taken
Using the kinematics equation
Y = v₀ t + (0.5) a t²
15 = (0) t + (0.5) (2.5) t²
t = 3.5 sec
Answer:
A
Explanation:
When friction slows a sliding block, <u>the kinetic energy of the block is transformed into internal energy
.</u>
<em>The frictional movement of two surfaces over one another leads to the conversion of some of their kinetic energies to another energy - heat or thermal energy. Hence, the temperatures of the objects are raised in the process. </em>
<u>Therefore, when a sliding block is slowed down due to friction, some of the kinetic energy of the block would be transformed into internal energy in the form of heat.</u>
The correct option is A.
Answer:
When the object is placed at the focus the image is formed at infinity.
Explanation:
When a ray passes through focus and incident on a concave mirror then it will travel parallel to principal axis after reflection.Hence the image is formed at infinity.
The true answer is the choice A
Scientists <span>can predict volcanic eruptions as long as adequate resources are available.Volcanic eruptions are one of the earthly activities which can be predicted by means of adequate resources (w</span><span>arming of the earth's crust, appearance of volcanic lava etc...). By contrast, earthquakes is a dangerous natural </span>disaster<span> that scientists cannot be predicted or mastering the time where it occurs.</span>
Answer:
1.Albert Einstein is considered as the one who developed the quantum theory. Although Planck gives the idea of quantized energy but Einstein gives the theory that not only the energy the wave or radiation itself is quantized.
2. Earnest Rutherford is considered as the father of nuclear science as he gives the concept of half life and perform tests of alpha and beta radiations in various elements.
3. Again Albert Einstein was the one who gave the theory of relativity in 1905.
Explanation:
